This is a shared equipment proposal to acquire a state-of-the-art cell analyzer/flow cytometer, under the auspices of the ORD Shared Equipment Program. The instrument proposed, a BD LSRFortessa, is an advanced digital cell analyzer that offers a broad range of critical, sensitive techniques to study phenotypes, behavior and activation of intracellular signaling pathways in samples from clinical research specimens or animal models. The present flow cytometer at our research center is over 11 years old. It has outlived its scientific usefulness and cannot be upgraded. The technology offered by the BD LSRFortessa is significantly more advanced, enabling measurement of subtle changes in cellular behavior and metabolism. This instrument therefore offers efficient, accurate new tools to answer key questions about human disease. Because the proposed instrument is centered on the measurement of cellular behavior and changes therein that occur with disease progression, it is widely applicable to our diverse community of researchers. This includes neuroscientists, researchers in diabetes and metabolism, cancer, vascular biology, and traumatic brain injury. We have identified 12 investigators that will use this instrument. Of these, 8 have VA-funded research programs (Major users, accounting for 75% of instrument time) while 4 minor users have research programs geographically located at VA Puget Sound Health Care System, and have research programs funded by NIH. We present in this proposal a comprehensive plan for the sharing, administration, and care of the instrument, and how different VA investigators will take advantage of this technology. In the Research Plan section of this proposal, we present a narrative for each VA investigator, and how they would take advantage of this shared instrument. Herein are excerpts to summarize some of these different uses: Measurements of platelet and monocyte activation in Veteran patients undergoing vascular surgery, through multicolor analyses of activation-dependent epitopes; analyses of intracellular signaling pathways from vital blood samples; measurements of platelet- and endothelial-derived microparticles. Measuring gene expression changes in response to drug treatment; quantitation of neurodegeneration- related aggregate formation in vivo, and cell viability analysis. Analyzing the effect of mutations in the STAT-1 protein on the numbers and types of cells present in atherosclerotic vessels. Delineating activation of intracellular stress signalng pathways (e.g. JNK signaling) and activation of apoptosis, which mediate amyloid-induced -cell loss as it relates to type 2 diabetes pathogenesis. Identification of specific brain cells e.g. neurons and microglia) from Alzheimer's and control postmortem brain tissues. Determining cellular phenotype of circulating or tissue-resident inflammatory cells for use in subsequent in vivo studies. In summary, this new instrument would provide a state-of-the-art scientific platform to support many VA investigators. The instrument will be located at the geographic center of our main research building, and managed by the established Cellular and Molecular Imaging Core. We have a well-developed administrative infrastructure for the management, scheduling, and support of the instrument.